1. Field of Invention
The present invention relates to a gripping member or collet of the type used in compression fittings for the connection of pipes. In particular, it relates to an annular collet that includes a generally longitudinal split defining a first and second end of the ring whereby one end is of a configuration to engage the other end to thereby prevent axial distortion of the collet during operation.
2. Background of the Invention
The present applicant is the owner of a number of patents dealing with pipe couplings. One of the applicant's earlier filed patent applications entitled ‘Pipe Coupling’ (the subject of PCT/AU02/00487) relates to a pipe coupling assembly that is significantly shorter than other pipe coupling assemblies that are generally too long for use in applications such as homes and meter boxes. Although the forthcoming description refers to the collet of the present invention being used in the pipe coupling of the applicant's previous patent, it is to be understood that the collet may well be incorporated into alternate pipe coupling configurations.
The pipe coupling assembly disclosed in PCT/AU02/00487 generally includes a nut, a body, a gripping member and a seal or o-ring. The nut engages the body through appropriate threads and includes a hooked projection having a sloping surface adapted to abut against and provide a force on a corresponding surface of the gripping member within the body. A pipe is inserted through the nut, gripping member and seal into the body. Tightening of the nut causes its sloped surface to engage a front portion of the gripping member that is then forced both radially and longitudinally. Radial compression results in the front portion of the gripping member engaging the pipe whilst longitudinal forcing causes it to be forced into the body simultaneously abutting against and compressing the seal whilst dragging the pipe further into the body.
The gripping member adapted to be used in such pipe coupling assemblies to engage the outer surface of polymeric or metal pipes are annular collets and have at their front portion inwardly directed barbed projections to thereby grip the pipes being connected. Molding of such rings requires them to be axially split so that they may be successfully jumped off a molding tool. The gripping member further includes a rear portion that is adapted to be located radially within the body such that the split ends abut. In order for leakage to be minimized or prevented, the rear face of the rear portion of the ring must uniformly compress the seal at all times during operation.
Various tests on the pipe coupling assembly of PCT/AU02/00487 have proven it to be a viable and successful alternative to larger known pipe coupling assemblies. However, it has been found that under significant pipe bending, the split ends of the gripping member axially distort thereby forming a non-uniform compression of the seal. The pipe coupling assembly therefore becomes prone to leakage.
It is therefore an object of the present invention to provide a gripping member or collet for pipe coupling that overcomes the abovementioned problems or at least provides the public with a useful alternative. The invention therefore relates to a collet having a split end configuration that prevents or at least seeks to minimize axial distortion of the ring.